Absolutely the best benchwork available today on a prodution basis is Model Railroad Bench Work.
Web site: www.modelrailroadbenchwork.com
You will be able to have some of the slickest curved benchwork available today. Custom curved framing to match the radius of your track and the depths of your valleys.
Strong, reusable, portable if needed, light weight and no dimensional lumber.
Most everything else is rigid, right angles and straight lines, all of which Model Railroad Benchwork can do, but what sets them apart is the curved benchwork they build.
Check out their website, examine their extensive "Gallery" of photos. No one else does this for model rail road benchwork.
The neat thing is that their pricing is in the ball park of squarish comparative products.
If I would ever have someone else build my benchwork, Model Railroad Benchwork is the ONLY company I would use.